Not sure why you are so down on Paul Whiteman, Brian Harvey.
When you think of the fact the big bands (even the sweet dance bands) were popular music back then and all had at least a bit of influence from jazz (if nothing else - swing feel), then Paul Whiteman WAS an important figure in many ways. If for nothing else, the personnel that went through his band - and the fact that he was a popular AMERICAN band and was known all over the world.
I would agree that the "King of Jazz" moniker might be a bit much for sure.
When asked in my clinics in schools about what makes jazz, I too feel that improvisation is a very important part of any form of jazz. But - in any big band situation there is going to be less room for improvisation, just because of the fact that much has to be written for the whole band to play in any arrangement. So - the idiom itself isn't as free and open as small group jazz.
One could even go so far as to say that many of the "trad" bands I have heard, don't play "real" jazz as much, because many of their solos are almost the same every time.
Mike Vax
Friends of Big Band Jazz, Prescott Jazz Summit,
Stan Kenton Alumni Band
www.mikevax.net
www.bigbandjazz.net
www.prescottjazz.com
www.getzen.com